Ashmolean Museum <1>
Monday Night –
My dear Mr Talbot
I return you your notes <2> a little altered – more verbally than in the sense.
I wish however to make a picture if I can by means of Gallic acid. This would be a triumphant proof of what at present I am not quite prepared to be positive about and I must therefore ask you to hold this point in abeyance for a little while – That it has an action there is no doubt –
I believe myself that it is probable there is a molecule common to Gallic & Pyrogallic acid <3> which is the active agent. But of this I am not prepared to offer proof except from analogy, drawn from other Chemical considerations.
I do not know if you want an opinion on any other points connected with the question. Let me know if you do. I had rather not go to Town just at present if I could help it. But I will obey your summons if you find it necessary.
Believe me Yours very truly
Nevil Story Maskelyne
1. Story-Maskelyne lectured on mineralogy and chemistry at the University of Oxford, and had a laboratory in the lower part of the museum building.
3. Part of Talbot’s case [against professional portrait-photographers who he claimed were infringing his photographic patents] rested upon the contention that as gallic acid and pyrogallic acid, though not identical substances, had an identical effect, the collodion process was a development of his Calotype process and was therefore covered by his patents. It was Rev Joseph Bancroft Reade (1801–1870), microscopist & photographer who first applied gallic acid, a tanning agent, to paper; during the trial to he claimed to have invented the Calotype process. [For a detailed account of this, see H.J.P. Arnold, William Henry Fox Talbot: Pioneer of photography and man of science (London: Hutchinson Benham, 1977, pp. 203–205.]